FFB plugin based on realistic Mz curve - Page 3

monty-cable · 14-08-2007, 03:55

Interesting thread....was wondering if you guys could benefit for more tire test data (Lateral Force and SAT). This data is for F2000 Avon radials, and demonstrates how SAT peaks much sooner than Lateral Force, and also shows how vertical load impacts how quickly SAT actually starts to drop.

LBodnar · 15-08-2007, 19:36

Quote:

Originally Posted by monty-cable

Interesting thread....was wondering if you guys could benefit for more tire test data (Lateral Force and SAT). This data is for F2000 Avon radials, and demonstrates how SAT peaks much sooner than Lateral Force, and also shows how vertical load impacts how quickly SAT actually starts to drop.

Thank you for the data! SAT looks very good. I can match that very accurately. But since I model the pneumatic trail, lateral force curve is part of the final result so it has to be either kept from rFactor data or redrawn from scratch.

Did you test the tyres yourself? There lateral force seems to be peaking very late (can't guess for sure but looks like beyond 10 degrees) - from the little data that I have seen it reminds me more of "truck tyres" that peak between 10 and 20 degrees slip angle as opposed to 6-10 degrees for "racing tyres." I can't comment what features make truck and street cars so different. Avon's are still radial, that supposed to have a crisp well-defined curve. I wonder if it is so gentle because they are slicks?
Leo

monty-cable · 15-08-2007, 22:27

No, I didn't test them...this is data that Avon puts out there as support for teams running their tires.

I think where the lateral force peaks at is related to a lot of things...like is the tire oversized for the application, does the compound mu value drop with high slip velocities, does the tire have a high lateral stiffness...

I think you can see the trend to that as load increases, the peak slip angle
moves outward...

I work for a tire company, used to design race tires. A key thing that you guys have hit on is that the driver only steers to the point where he feels the aligning torque level off or start to drop. This is why F1 teams years ago moved to higher caster values, to push that peak slip angle for Align Torque further out. Even though this forced them to run power steering (added weight) it was worth it.

Another way we can plot the Lateral Force curves is to show them as a function of Mu. They should show us that as load increases, the Mu decreases, because friction of rubber has a pressure dependency. I'll make some plots and see if this data agrees with that.

LBodnar · 15-08-2007, 23:00

Quote:

Originally Posted by monty-cable

No, I didn't test them...this is data that Avon puts out there as support for teams running their tires.

I think where the lateral force peaks at is related to a lot of things...like is the tire oversized for the application, does the compound mu value drop with high slip velocities, does the tire have a high lateral stiffness...

I think you can see the trend to that as load increases, the peak slip angle
moves outward...

I work for a tire company, used to design race tires. A key thing that you guys have hit on is that the driver only steers to the point where he feels the aligning torque level off or start to drop. This is why F1 teams years ago moved to higher caster values, to push that peak slip angle for Align Torque further out. Even though this forced them to run power steering (added weight) it was worth it.

Another way we can plot the Lateral Force curves is to show them as a function of Mu. They should show us that as load increases, the Mu decreases, because friction of rubber has a pressure dependency. I'll make some plots and see if this data agrees with that.

I'd be grateful to see as much data as possible! Out of curiosity - I know it is very difficult to test different temperatures on the rig but what is happening with slip curves when temperatures go up? I assume the tyre becomes softer and first gets a better grip (higher peak) but having crossed over the optimal temperature it gets structurally softer and the cornering stiffness drops? Just speculating!

monty-cable · 16-08-2007, 03:56

If you are doing it right...you try to warm the tire up first, getting both the tread and the carcass up to temperature...then you start the test. I think there is maybe too much made of getting tires so hot that the grip goes down. I believe this statement is partially true, but it is related to the pressure building inside the tire, not the Mu of the compound dropping.

Besides pressure buildup, the only other issue with heat is durability. Get them too hot, they blister.

Here's a picture taken from the Avon Data demonstrating the Mu effect as a function of load...

LBodnar · 16-08-2007, 11:42

Just to be clear, do you define Mu as Mu = Fy/Fz ?
At least it looks pretty much so - if I recall correctly, the peak value of Fy/Fz drops off slightly with increasing Fz and the peak itself is reached at lower angles under lighter loads.

monty-cable · 18-08-2007, 16:25

Yes...that's the right definition. Within the data I first sent is also the effect of camber on these curves.

Hope this helps...

For temperature sensitivity, I would increase grip with temp up to 200 F, then hold it constant until you reach a running temperature that results in tire temperature measured in the pits after an in-lap of 300 F. When that running temp is reached, grip should be reduced significantly because the tire will start to blister....dunno if it is possible in rFactor...but once that temp is reached, and blisters start, a small vibration should be noticed for that particular wheel position...

irousso · 20-08-2007, 16:11

LBodnar - I really love your plugin! thanks!
One qustion - is it possible somehow to disable the plugin at speed 0 - to avoid the false oscillations? I guess you can set that when speed is 0.001 then it is back on or something like that...
Itay

Fjalla · 20-08-2007, 16:20

Yes, I too really like the FFB feeling I'm getting now.
Have made separate .ini files now for all my mods

It would sure be great if you can work together with Techade and Kangaloosh to make it a more userfriendly plugin. (realfeel?)
Anyways, great work!

TechAde · 20-08-2007, 18:06

Quote:

Originally Posted by Fjalla

It would sure be great if you can work together with Techade and Kangaloosh to make it a more userfriendly plugin. (realfeel?)

Watch this space (not too closely though, unfortunately Real Life (tm) has to take priority for a few days)

Fjalla · 21-08-2007, 09:42

Sure will TechAde, good luck.

Zalo · 21-08-2007, 15:02

Great thread, plugin is about to be tested!

Thanks a lot for all the effort and knowledge you guys are putting in to the rFactor community. Realy great!

Fjalla · 27-08-2007, 09:43

Just wondering, how are you guys coming along with implementing this together with realfeel?

LBodnar · 27-08-2007, 10:54

Ade has already integrated the low speed/stationary forces into RealFeal and it works great. The rest of the code needs some cleanup/commenting from my side before I pass it over to him but I am a bit strapped for time at this moment due to a couple of big projects. I will definitely do it, just give me some time!

Fjalla · 27-08-2007, 11:05

That's good to hear. I was not pushing Leo

Just looking forward.

irousso · 27-08-2007, 12:38

I have a (probably) stupid question...
Since I never drove an F1 car or any car with downforce, as the speed increase the downforce increase as well - shouldn't turning the wheels should become harder than when the car is standing? its as if the mass of the car becomes larger with speed... am I totally wrong here?
Cheers,
Itay

Semus · 29-08-2007, 05:26

Quote:

Originally Posted by R G

F1 cars have power steering.

RG

I think most race cars do these days.

One question to Leo......Will this plugin work with any mod? Are there some mods that I should keep this plugin away from? And are the INI entries as easy to modify as RealFeel? From reading this thread, apart from acquiring a massive headache somewhere on page two, I am gathering that these two separate plugins are now working together, but independently? Did I just say that? Anyhow, what I meant was, we can use the two plugins separately but if both plugins are installed, they will compliment each other?

I think that was about ten questions. Sorry about that. Having excused all the inaccuracies in my post, what say you?

Frank-br · 30-08-2007, 21:11

Loved the plugin with F1 cars but i dont like the effect when passing over curbs... There is a way to reduce this rumble effect without messing with the other bumps forces? I hope there is a way to disable the plugin from a hotkey, its a pain to have to delete the dll and the ini everytime i whant to go back to the default force-feedback.

LBodnar · 30-08-2007, 21:20

Quote:

Originally Posted by Frank-br

Loved the plugin with F1 cars but i dont like the effect when passing over curbs... There is a way to reduce this rumble effect without messing with the other bumps forces? I hope there is a way to disable the plugin from a hotkey, its a pain to have to delete the dll and the ini everytime i whant to go back to the default force-feedback.

Try setting this value in the .ini file lower or to zero:
1.0 Road bumps feeling on the wheel

If this does not help then the rumble is coming from the rFactor effects, go to controller.ini file and reduce this:

FFB rumble strip magnitude="0.xxxxx" // How strong the rumble strip rumble is. Range 0.0 to 1.0, 0.0 disables effect.

You can leave .ini file in place to remove the plugin, just delete the .dll

Ade will incorporate this all into the RealFeal at some point (stationary/low speed tyres are already there) after I have sent him the code. I am very busy for the next few days but next week we should have a go at it.

Cheers!

Frank-br · 30-08-2007, 22:30

Thanks, but like i said, reducing the bump feeling in the ini reduce the bumps feeling overall, not only in the curbs. I like the bumps effect on the road and want to reduce only the curbs forces. I'll try the FFB rumble strip magnitude settings in the ini but i was thinking the plugin use internal settings and not the controller.ini settings.

LBodnar · 30-08-2007, 22:37

Quote:

Originally Posted by Frank-br

Thanks, but like i said, reducing the bump feeling in the ini reduce the bumps feeling overall, not only in the curbs. I like the bumps effect on the road and want to reduce only the curbs forces. I'll try the FFB rumble strip magnitude settings in the ini but i was thinking the plugin use internal settings and not the controller.ini settings.

The plugin simply transmits roll axis angular acceleration to the wheel. It should only give a bump if your wheel drops down or jums up onto the curb or other road surface.

The controller.ini setting sets the rumble strip vibration and a constant pull if you keep riding a wheel on the strip. This effect applied on top of calculated plugin forces later inside rFactor itself.

So is it a single jerk or a rrrrrrrrumble/pull that you want to get rid of?

Frank-br · 30-08-2007, 23:09

Thanks for the explanation. I'm not sure its really the rumble strip force because when i pass over some curbs there arent that violent jerk, its the right term. When playing with ISI force-feedback i can pass the curbs at Monza GTR2 just fine, for example, but with the plugin there are a very strong jerk on the wheel. Not that rumble effect feeling i like but more like the car hits a rock... hope you can understand my bad english.

LBodnar · 31-08-2007, 00:09

I see what you mean. It was a quick fix effect - I wll look at either limiting or damping the roll forces to reduce their dynamic range.

Zalo · 31-08-2007, 01:12

Great work Leo, for most of ny mods I use LeoFFB now.

Can we expect an update soon?

cobragt · 31-08-2007, 01:56

Hi Guys,

I was wondering if any of you would know how to correct very high temps from the front tires?

I race with F1 Champions and every track we race on either the FRONT LEFT or FRONT RIGHT tire heats up to about 130+ degrees.

NEVER do both tires get that hot at the same time, it is one side or the other.

Would anyone know how to correct this?

Thanks guys

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14-08-2007, 03:55	#51
monty-cable Registered Join Date: May 2005	Interesting thread....was wondering if you guys could benefit for more tire test data (Lateral Force and SAT). This data is for F2000 Avon radials, and demonstrates how SAT peaks much sooner than Lateral Force, and also shows how vertical load impacts how quickly SAT actually starts to drop.

15-08-2007, 22:27	#53
monty-cable Registered Join Date: May 2005	No, I didn't test them...this is data that Avon puts out there as support for teams running their tires. I think where the lateral force peaks at is related to a lot of things...like is the tire oversized for the application, does the compound mu value drop with high slip velocities, does the tire have a high lateral stiffness... I think you can see the trend to that as load increases, the peak slip angle moves outward... I work for a tire company, used to design race tires. A key thing that you guys have hit on is that the driver only steers to the point where he feels the aligning torque level off or start to drop. This is why F1 teams years ago moved to higher caster values, to push that peak slip angle for Align Torque further out. Even though this forced them to run power steering (added weight) it was worth it. Another way we can plot the Lateral Force curves is to show them as a function of Mu. They should show us that as load increases, the Mu decreases, because friction of rubber has a pressure dependency. I'll make some plots and see if this data agrees with that.

16-08-2007, 03:56	#55
monty-cable Registered Join Date: May 2005	If you are doing it right...you try to warm the tire up first, getting both the tread and the carcass up to temperature...then you start the test. I think there is maybe too much made of getting tires so hot that the grip goes down. I believe this statement is partially true, but it is related to the pressure building inside the tire, not the Mu of the compound dropping. Besides pressure buildup, the only other issue with heat is durability. Get them too hot, they blister. Here's a picture taken from the Avon Data demonstrating the Mu effect as a function of load...

16-08-2007, 11:42	#56
LBodnar Registered Join Date: Feb 2006 Location: UK	Just to be clear, do you define Mu as Mu = Fy/Fz ? At least it looks pretty much so - if I recall correctly, the peak value of Fy/Fz drops off slightly with increasing Fz and the peak itself is reached at lower angles under lighter loads.

18-08-2007, 16:25	#57
monty-cable Registered Join Date: May 2005	Yes...that's the right definition. Within the data I first sent is also the effect of camber on these curves. Hope this helps... For temperature sensitivity, I would increase grip with temp up to 200 F, then hold it constant until you reach a running temperature that results in tire temperature measured in the pits after an in-lap of 300 F. When that running temp is reached, grip should be reduced significantly because the tire will start to blister....dunno if it is possible in rFactor...but once that temp is reached, and blisters start, a small vibration should be noticed for that particular wheel position...

20-08-2007, 16:11	#58
irousso Registered Join Date: Feb 2003 Age: 40	LBodnar - I really love your plugin! thanks! One qustion - is it possible somehow to disable the plugin at speed 0 - to avoid the false oscillations? I guess you can set that when speed is 0.001 then it is back on or something like that... Itay

20-08-2007, 16:20	#59
Fjalla Registered Join Date: Apr 2006 Location: Netherlands Age: 32	Yes, I too really like the FFB feeling I'm getting now. Have made separate .ini files now for all my mods It would sure be great if you can work together with Techade and Kangaloosh to make it a more userfriendly plugin. (realfeel?) Anyways, great work!

21-08-2007, 09:42	#61
Fjalla Registered Join Date: Apr 2006 Location: Netherlands Age: 32	Sure will TechAde, good luck.

21-08-2007, 15:02	#62
Zalo Registered Join Date: Jun 2007 Location: Netherlands Age: 33	Great thread, plugin is about to be tested! Thanks a lot for all the effort and knowledge you guys are putting in to the rFactor community. Realy great!

27-08-2007, 09:43	#63
Fjalla Registered Join Date: Apr 2006 Location: Netherlands Age: 32	Just wondering, how are you guys coming along with implementing this together with realfeel?

27-08-2007, 10:54	#64
LBodnar Registered Join Date: Feb 2006 Location: UK	Ade has already integrated the low speed/stationary forces into RealFeal and it works great. The rest of the code needs some cleanup/commenting from my side before I pass it over to him but I am a bit strapped for time at this moment due to a couple of big projects. I will definitely do it, just give me some time!

27-08-2007, 11:05	#65
Fjalla Registered Join Date: Apr 2006 Location: Netherlands Age: 32	That's good to hear. I was not pushing Leo Just looking forward.

27-08-2007, 12:38	#66
irousso Registered Join Date: Feb 2003 Age: 40	I have a (probably) stupid question... Since I never drove an F1 car or any car with downforce, as the speed increase the downforce increase as well - shouldn't turning the wheels should become harder than when the car is standing? its as if the mass of the car becomes larger with speed... am I totally wrong here? Cheers, Itay

30-08-2007, 21:11	#68
Frank-br Registered Join Date: Jun 2001 Location: Londrina-PR-Brazil	Loved the plugin with F1 cars but i dont like the effect when passing over curbs... There is a way to reduce this rumble effect without messing with the other bumps forces? I hope there is a way to disable the plugin from a hotkey, its a pain to have to delete the dll and the ini everytime i whant to go back to the default force-feedback.

30-08-2007, 22:30	#70
Frank-br Registered Join Date: Jun 2001 Location: Londrina-PR-Brazil	Thanks, but like i said, reducing the bump feeling in the ini reduce the bumps feeling overall, not only in the curbs. I like the bumps effect on the road and want to reduce only the curbs forces. I'll try the FFB rumble strip magnitude settings in the ini but i was thinking the plugin use internal settings and not the controller.ini settings.

30-08-2007, 23:09	#72
Frank-br Registered Join Date: Jun 2001 Location: Londrina-PR-Brazil	Thanks for the explanation. I'm not sure its really the rumble strip force because when i pass over some curbs there arent that violent jerk, its the right term. When playing with ISI force-feedback i can pass the curbs at Monza GTR2 just fine, for example, but with the plugin there are a very strong jerk on the wheel. Not that rumble effect feeling i like but more like the car hits a rock... hope you can understand my bad english.

31-08-2007, 00:09	#73
LBodnar Registered Join Date: Feb 2006 Location: UK	I see what you mean. It was a quick fix effect - I wll look at either limiting or damping the roll forces to reduce their dynamic range.

31-08-2007, 01:12	#74
Zalo Registered Join Date: Jun 2007 Location: Netherlands Age: 33	Great work Leo, for most of ny mods I use LeoFFB now. Can we expect an update soon?

31-08-2007, 01:56	#75
cobragt Registered Join Date: Jul 2005 Location: Toronto, Canada Age: 44	Hi Guys, I was wondering if any of you would know how to correct very high temps from the front tires? I race with F1 Champions and every track we race on either the FRONT LEFT or FRONT RIGHT tire heats up to about 130+ degrees. NEVER do both tires get that hot at the same time, it is one side or the other. Would anyone know how to correct this? Thanks guys